{"id":47732,"date":"2023-07-19T14:15:59","date_gmt":"2023-07-19T14:15:59","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=120559"},"modified":"2023-07-19T14:32:31","modified_gmt":"2023-07-19T14:32:31","slug":"astronomers-find-evidence-of-two-planets-sharing-the-same-orbit-around-a-star","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/astronomers-find-evidence-of-two-planets-sharing-the-same-orbit-around-a-star\/","title":{"rendered":"Astronomers find evidence of two planets sharing the same orbit around a star"},"content":{"rendered":"

Could two similar worlds orbit the same star, side by side? A new study appears to have discovered just that. <\/p>

By Iain Todd\n \t\t<\/p>

Published: Wednesday, 19 July 2023 at 12:00 am<\/p>

\n\n

Astronomers have discovered strong evidence of two planets sharing the same orbit around a star.<\/p>\n

A new study reveals the detection of a cloud of debris sharing another planet\u2019s orbit.<\/p>\n

This could be the building blocks of a new planet, or the remnants of one already formed.<\/p>\n

If confirmed, it would be the first time that the \u2018sibling\u2019 of a planet orbiting a distant star has ever been seen.<\/p>\n

\""Image\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Image showing planetary system PDS 70, with a star at its centre. Highlighted in a yellow circle is planet PDS 70b, and highlighted in a dotted yellow circle is a potential Trojan planet sharing the same orbit. Credit: ALMA (ESO\/NAOJ\/NRAO) \/Balsalobre-Ruza et al.<\/span><\/figcaption><\/div>\n

The discovery adds further evidence to the existence of so-called Trojan planets, or co-orbital planets, which is when pairs of planets of similar mass share the same orbit around their host star.<\/p>\n

A similar example can be found in our own Solar System in the Trojan asteroids<\/a> of Jupiter, which are more than 12,000 rocky bodies that share Jupiter\u2019s orbit around our Sun.<\/p>\n

But finding a Trojan planet has so far proven difficult.<\/p>\n

\""An\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
An artist\u2019s impression of the Trojan asteroids, which share the same orbital path around the Sun as gas giant Jupiter. Credit: NASA\/JPL-Caltech<\/span><\/figcaption><\/div>\n

A team of astronomers using the Atacama Large Millimeter\/submillimeter Array (ALMA) in the Atacama Desert of Chile observed the PDS 70 system, which is a star 400 lightyears away known to host two Jupiter-like planets called PDS 70b and PDS 70c.<\/p>\n

They spotted a cloud of debris at the location in PDS 70b\u2019s orbit where Trojans are thought to exist.<\/p>\n

Studying the Lagrangian zones \u2013 regions in a planet\u2019s orbit where gravitational equilibrium between the planet and host star can trap cosmic material \u2013 around PDS 70\u2019s orbit, the astronomers found evidence of a cloud of debris.<\/p>\n

That debris has a mass up to about twice that of Earth\u2019s Moon, and may well be evidence of a Trojan planet sharing the same orbit around the host star.<\/p>\n